Slide projector polarizing slide unit

ABSTRACT

A polarizing slide unit of conventional 35 mm. photographic slide proportions or other standard slide proportions adapted to be handled or projected by a conventional diascope or slide projector. The polarizing slide unit includes a polarizing light mount assembly of hollow construction having slot or pocket means adapted to removably receive a rock thin section or the like and which may be of standard or conventional microscope slide proportions. The polarizing mount assembly removably supports a rock section slide specimen in sandwich fashion between two polarizing filter panes positioned relative to one another with mutually crossed polarizing axes. The slide unit combination of the rock specimen thin section and the polarizing mount assembly is adapted to be positioned in the light system of a conventional slide projector and to project a polarized light image of the thin section specimen on a projection screen surface.

United Sta/l 557K Kirst sum: PROJECTOR POLAR'IZING SLIDE UNIT Paul W.Klrst, 6010 S. W. 95th CL, Miami, Fla. 33143 Filed: Mar. 11, 1970 Appl.No.: 18,572

Inventor:

[56] References Cited UNITED STATES PATENTS Mainardi et a1 ..353/8Primary Examiner-David Schonberg Assistant ExaminerPaul R. MillerAttomey-Elliott Stern [57] ABSTRACT A polarizing slide unit ofconventional 35 mm. photographic slide proportions or other standardslide proportions adapted to be handled or projected by a conventionaldiascope or slide projector. The polarizing slide unit includes apolarizing light mount assembly of hollow construction having slot orpocket means adapted to removably receive a rock thin section or thelike and which may be of standard or conventional microscope slideproportions. The polarizing mount assembly removably supports a rocksection slide specimen in sandwich fashion between two polarizing filterpanes positioned relative to one another with mutually crossedpolarizing axes. The slide unit combination of the rock specimen thinsection and the polarizing mount assembly is adapted to be positioned inthe light system of a conventional slide projector and to project apolarized light image of the thin section specimen on a projectionscreen surface.

10 Claims, 4 Drawing Figures Patented March 14, 1972 3,649,100

l6 g I:

INVENTOR. @904 1a KIRST 32 B HTTOAIUEX BACKGROUND OF THE INVENTION 1.Field of the Invention Relates to optical petrography or crystallographyand particularly relates to the optical examination of nonopaqueanistropic mineral compositions in thin section mineral specimens.

2. Description of the Prior Art The science of petrography is largelybased on the examination of rock specimens in thin section andprincipally through the use of a microscope instrument with polarizingmeans or through use of a special slide projector having polarizingmeans and operative for projecting the rock specimen image upon aprojector screen surface. The instant invention is directed mainlytoward improvements in slide projection means of rock specimenexamination.

The prior art thin section projector has certain advantages over themicroscope viewing of thin section rock specimen slides. The projectionof a rock specimen image upon a projection screen surface isparticularly advantageous in classroom instruction or the like and wherea group of persons may simultaneously view the specimen image on theprojector screen. The prior art thin section projector is of specialdesign having polarizing and analyzing light filter means for theexamination and identification of the various rock or mineralstructures. A principal disadvantage with the prior art thin sectionprojector is the relatively high cost of the instrument. The typicalhigh school earth science department or the small college geologydepartment often may not be able to afford to purchase the expensivethin section projector. Also, many of the prior art thin sectionprojectors will not project a specimen image with as much magnificationand light intensity as is often desired in classroom or groupinstruction technique. This is particularly noticeable in classroomviewing wherein the room may not be darkened sufficiently for maximumimage contrast on the projection screen.

SUMMARY OF THE INVENTION The instant invention provides a slide orpolarizing light unit, preferably of standard 35 mm. size adapted to besubstituted for the typical 35 mm. photographic slide transparency in autility or domestic type diascope or slide projector. The polarizingslide unit of the instant invention includes a thin section rockspecimen or the like removably received interposedly between a pair ofpolarizing pane members having crossed polarizing axes. The polarizingslide unit is adapted to be inserted in the typical domestic type slideprojector and is operative for projecting an image with as much or moremagnification and light intensity as the specially designed thin sectionprojector. Since the typical domestic type slide projector isconsiderably less expensive than the scientific specially designed thinsection projector, and is generally available for other purposes, thepolarizing slide unit of the invention provides relatively inexpensivemeans for obtaining suitable image projection of a rock specimen sectionor the like. The polarizing slide unit of the instant invention whenused in conjunction with a domestic type slide projector, providesinexpensive means for examining the optical properties of anistropicminerals and the inspection and observation of crystal form, habit,texture, twinning, interference color and other nonopaque mineralcharacteristics.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation view of apolarizing slide unit of the instant invention shown as in an operativedisposition in a FlGr'4i's a vertical enlarged section of the polarizingslide unit of FIG. 3 illustrating the thin section specimen nested withthe polarizing mount assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT v The polarizing slide unit ofthe instant invention is generally indicated by reference character 12and is shown and described in conjunction with a conventional diascopeor slide projector 14 conventionally operative for projecting the imagesof framed photographic transparencies or photographic slides of standard35 mm. size or other standard size. The diascope typically includeshousing structure 16 enclosing light source means in the form of anincandescent light bulb 18; a condenser lens system 20; a projectionlens 22; and slide transparency support means typically including aslide carriage 24 manually shiftable in the housing 16 and having meansfor removably receiving a selected 35 mm. slide transparency. The slidecarriage 24 includes hand grip means 26 for manually actuating the slidecarriage between a pushed-in position for projecting the image of aslide transparency, and a pulled-out position for permitting changing ofa slide transparency (see respectively the full line and broken lineshowing of the slide carriage 24 in FIG. 2). A'projection screen 28typically is provided for viewing the image projected from the diascopeinstrument l4.

Referring now to FIG. 3, the polarizing slide unit 12 is of a standardphotographic slide transparency size, as for example 35 mm. slidetransparency size, and is adapted to be supported in the slide carriage24 of projector 14 in lieu of a typical photographic slide transparency(not shown). The polarizing slide unit 12 of the instant inventionbasically includes specimen slide means 30 removably received in ahollow polarizing mount assembly 32 of standard photographic slidetransparency proportion, as for example a 35 mm. slide pro-' portion.The specimen slide means 30 also may be of typical microscope slideconfiguration (as shown in the drawing) and includes a transparentobject plate 34 laminatingly supporting a thin section specimen 36 in acentral zone thereof. By way of exemplification, the specimen slidemeans 30 will be considered as being of the type utilized in opticalmineralogy or petrography and thus the thin section specimen 36 is ofnonopaque mineral or rock composition. The thin section specimen 36 islaminatingly bonded on one face surface of the transparent object plate34 by suitable adhesive or cement means (not shown).

The polarizing mount assembly 32 constitutes the essential part of theinvention and preferably includes a first polarizing pane 38, a secondpolarizing pane 40, and spacer frame means or support structure 42supporting the first and second panes 38, 40 in closely spaced parallelarrangement and defining a slot pocket or opening 43 for removablyreceiving the polarizing slide unit 12 (see FIGS. 3 and 4). The firstand second polarizing panes 38, 40 each are preferably of artificiallyprepared polarizing film material and are supported in parallel relationby spacer frame means 42 with the light polarizing axes of the panesbeing mutually perpendicular. The arrows 44, 46 in FIG. 3 indicaterespectively the light polarization axes of the first and secondpolarizing panes 38, 40.

The polarizing slide unit 12 is adapted to be supported in the diascopeinstrument 14 with the first polarizing pane 38 being oriented towardthe light source and condenser lens 18, 20; the thin section specimen 36is adapted to be illuminated by transmitted light passing through thespecimen slide means (see FIG. 4 and light rays indicated by arrows).The first polarizing pane 38 defines the polarizer and second pane 40theanalyzer in the optical examination of the specimen slide means 30and the polarized light image projection of the thin section specimen36.

The support structure 42 of the polarizing mount assembly 32 preferablyis in the form of a flattened U-shaped frame member 48 preferably formedof opaque, heat-resistant sheet or plate plastic stock material. Thefirst and second polarizing panes 38, 40 and the U-shaped frame member48 preferably are laminatingly secured together by fastener members 50arranged along opposite side edges of the polarizing mount assembly 32.The polarizing mount assembly 32 is adapted to removably receive thespecimen slide 30 in the slot opening 43 thereof with the parallelextending opposite exterior edge margins 52, 52 of the slide extendingcontiguous to respective interior edge margins 54, 54 of the mountassembly frame member 48 (see FIG. 3). I

The upwardly oriented edge margin 56 of the horizontal bight portion 58of frame member 48 defines stop means for the specimen slide element 30when it is received in slot opening 43 of the polarizing mount assembly32. The lower edge margin 60 of the specimen slide element 30 abuttinglyengages the edge margin 56 of frame member 48 and positions the thinsection rock specimen 36 at a disposition fully between the parallelarranged polarizing panes 38, 40. The upper edge margins respectively ofthe first and second polarizing panes 38, 40 preferably are scalloped orcut'crescent shape as indicated at 62 for permitting ready removal orinsertion of a specimen slide element 30 respectively out of or into theslot opening 43 of the polarizing mount assembly 32.

The rectangular peripheries of the first and second polarizing panes 38.40 and the periphery of frame member 48 preferably are coextensive inrectangular size corresponding with the rectangular size of a typicalstandard photographic slide transparency; the thickness of thepolarizing mount assembly 32 also corresponds substantially with thethickness of a conventional photographic slide transparency (not shown).The polarizing mount assembly 32 and thus the outer surfaceconfiguration of a polarizing slide unit 12 is sized to correspond witha particular size photographic slide and to be operative in a particulardiascope or slide projector 14 designed for showing or handling astandard size photographic slide.

in the use of the polarizing slide unit 12, a selected specimen slide 30is inserted in the slot opening 43 of the polarizing mount assembly 32with the thin section specimen 36 received between the polarizer andanalyzer panes 38, 40. With the slide carriage 24 of the diascopeinstrument [4 in an outwardly retracted disposition (shown in brokenlines in FIG. 2) the slide unit 12 is vertically fitted in the slidecarriage 24 and the slide carriage moved inwardly (full line showing ofthe carriage in FIG. 2). The polarizing slide unit 12 is positioned infront of the condenser lens system and the light passing through thecondenser lens illuminates the specimen slide section 36 and projectsthe image of the specimen on the surface of the projection screen 28.The cross polarizing panes 38, 40, in the optical examination of aselected anistropic thin section specimen, projects a polarized lightimage of the specimen upon projection screen 28' and the opticalproperties of crystallization, habit, interference color, texture,twinning and other optical properties of the specimen may be ascertainedby comparison, estimation or measurement procedure. The

first polarizing pane 38, called the polarizer, produces plane polarizedlight which then enters the material to be examined (i.e., minerals ofthe rock). The material, if it has optical rotary power, will permitcomponents of this plane polarized light to enter and pass through onlywhile vibrating in one of two directions within the material. The lightwhich passes out through the other side of the material is vibrating intwo directions (two rays vibrating at 90). The rays traveling in thesetwo different vibration directions travel at different speeds throughthe material. Thus when they emerge and pass through the secondpolarizing pane (the analyzer 40) they are resolved back into onedirection of vibration; but since they are out of phase, it producesinterference colors.

Although the instant invention is described primarily as being useful inthe field of optical petrography and the examination of thin rocksection specimens, it will be understood that the polarizing slide unit12 is useful for other purposes. It can be used for viewing theinterference colors of any material which possesses optical rotarypower, in thin section or mounted in any other way. For rock specimensit serves--todetermine crystal forms, if present;' mineral cleavages orfractures, and their degree of development and mutual angular relations;shape of crystals; inclusions, intergrowths and alterations, if present;and twinning, if present. The invention is also useful to distinguishbetween similar materials with difi'erent crystal structures, such assugars, based on their different birefringence, or for determiningwhether a material is optically active.

My invention is designed also for viewing a biological wet mount betweenmicroscope slide and cover glass. Here the interference colors can beused to determine the birefringence of that substance. lf pollutedwater, for example. contains optically active biological material, theconcentration of this pollutant would produce a measurable quanta oflight (interference colors) which could be measured with a photocell.

ln testing sugar solutions, biological compositions or other liquidsolutions by the medium of polarized light, the

specimen slide means 30 will be of somewhat different form. Thepreparation of a microscope slide for examination of a sugar solution orbiological material is well known to those in the art. The specimenslide means may be of so-called wet mount form and include an objectplate and a cover plate sup porting a liquid or biological specimentherebetween. It will be understood that a slide means 30 designed forexamination of liquid or biological specimens may readily be inserted inthe slot opening 43 of the polarizing mount assembly 32 and supported inthe diascope instrument 14 for projecting a polarized light image of thespecimen.

All of these features would be enlarged by the lenses in a standardslide projector, the degree of enlargement depending upon the projectiondistance, and projected as a large picture suitable for viewing by alarge group of people.

Although the instant invention is described in what is presentlyconceived to be the preferred embodiment thereof, it is understood thatcertain changes and modifications may be made without departing from thespirit and scope of the invention.

What is claimed is:

l. A polarizing slide unit for use in a diascope type slide projectorfor use in optical petrography in the study of crystalline nonopaquecompositions, the polarizing slide unit comprising,

A. specimen slide means including a thin flat specimen;

B. a polarizing mount assembly removably mounting said specimen slidemeans and including 1. a first polarizing pane, 2. a second polarizingpane, and

3. support structure firmly maintaining said first and second panes inclosely spaced parallel arrangement,

4. said mount assembly defining a slot opening between said polarizingpanes for removably receiving said specimen slide means therebetween,

5. said first and second panes having their respective polarizing axesarranged in perpendicular relation with respect to each other;

C. said polarizing slide unit being adapted to be removably positionedin the diascope instrument for projecting a polarized light image of thethin section specimen or the like upon a projection screen surface.

2. The unit as set forth in claim 1 wherein the specimen comprises anonopaque rock section.

3. The unit as set forth in claim 1 wherein the specimen slide meanscomprises an object plate of planar form adapted for receipt in the slotopening of said mount assembly.

4. The unit as set forth in claim 3 wherein adhesive means is providedto secure the rock section specimen to said object plate? 5. The unit asset forth in claim 4 wherein the support structure comprises spacerframe means between the polarizing panes.

6. The unit as set forth in claim 1 wherein the frame means includesstop means in opposition to said slot opening to limit penetration ofthe slide means and to position the slide means within said mountassembly.

7. A polarizing slide unit as set forth in claim 1 wherein said specimenslide means is of generally rectangular configuration and havingopposite exterior edge margins, and wherein said support structure ofsaid polarizing mount assembly is arranged interposedly between thefirst and second polarizing panes and defines generally parallelconfronting interior edge margins lying contiguous the opposite exterioredge margins of said specimen slide means when the same is received insaid polarizing-panes in closely spaced parallel arrangement anddefining a slot opening between the panes for removably receiving amicroscope type slide,

D. said first and second panes being supported with the polarizing axesthereof in generally perpendicular relatron;

E. said light polarizing mount assembly being adapted to receive amicroscope type slide nested therein and to be removably positioned inthe diascope instrument for projecting a polarized light image of theanistropic rock section specimen or the like upon a projection screensurface.

9. The mount assembly as set forth in claim 8 wherein said supportstructure comprises frame means defining a slot pocket between thepolarizing panes adapted to nest a microscope type slide.

10. The mount assembly as set forth in claim 9 which includes stop meansto position a microscope slide between the polarizing panes of saidmount assembly.

1. A polarizing slide unit for use in a diascope type slide projectorfor use in optical petrography in the study of crystalline nonopaquecompositions, the polarizing slide unit comprising, A. specimen slidemeans including a thin flat specimen; B. a polarizing mount assemblyremovably mounting said specimen slide means and including,
 1. a firstpolarizing pane,
 2. a second polarizing pane, and
 3. support structurefirmly maintaining said first and second panes in closely spacedparallel arrangement,
 4. said mount assembly defining a slot openingbetween said polarizing panes for removably receiving said specimenslide means therebetween,
 5. said first and second panes having theirrespective polarizing axes arranged in perpendicular relation withrespect to each other; C. said polarizing slide unit being adapted to beremovably positioned in the diascope instrument for projecting apolarized light image of the thin section specimen or the like upon aprojection screen surface.
 2. a second polarizing pane, and
 2. The unitas set forth in claim 1 wherein the specimen comprises a nonopaque rocksection.
 3. The unit as set forth in claim 1 wherein the specimen slidemeans comprises an object plate of planar form adapted for recipt in theslot opening of said mount assembly.
 3. support structure firmlymaintaining said first and second panes in closely spaced parallelarrangement,
 4. said mount assembly defining a slot opening between saidpolarizing panes for removably receiving said specimen slide meanstherebetween,
 4. The unit as set forth in claim 3 wherein adhesive meansis provided to secure the rock section specimen to said object plate. 5.The unit as set forth in claim 4 wherein the support structure comprisesspacer frame means between the polarizing panes.
 5. said first andsecond panes having their respective polarizing axes arranged inperpendicular relation with respect to each other; C. said polarizingslide unit being adapted to be removably positioned in the diascopeinstrument for projecting a polarized light image of the thin sectionspecimen or the like upon a projection screen surface.
 6. The unit asset forth in claim 1 wherein the frame means includes stop means inopposition to said slot opening to limit penetration of the slide meansand to position the slide means within said mount assembly.
 7. Apolarizing slide unit as set forth in claim 1 wherein said specimenslide means is of generally rectangular configuration and havingopposite exterior edge margins, and wherein said support structure ofsaid polarizing mount assembly is arranged interposedly between thefirst and second polarizing panes and defines generally parallelconfronting interior edge margins lying contiguous the opposite exterioredge margins of said specimen slide means when the same is received insaid slot opening.
 8. For use with a conventional diascope typeprojector adapted for handling framed photographic slide transparenciesof standard proportions, and with a conventional microscope type slidemounting a thin section anistropic rock specimen of standard proportion,the combination of a light polarizing mount assembly adapted todetachably mount said microscope type slide for projection of the thinsection image by the diascope instrument, said light polarizing mountassembly comprising, A. a first polarizing pane, B. a second polarizingpane, and C. support structure firmly maintaining said first and secondpolarizing panes in closely spaced parallel arrangement and defining aslot opening between the panes for removably receiving a microscope typeslide, D. said first and second panes being supported with thepolarizing axes thereof in generally perpendicular relation; E. saidlight polarizing mount assembly being adapted to receive a microscopetype slide nested therein and to be removably positioned in the diascopeinstrument for projecting a polarized light image of the anistropic rocksection specimen or the like upon a projection screen surface.
 9. Themount assembly as set forth in claim 8 wherein said support structurecomprises frame means defining a slot pocket between the polarizingpanes adapted to nest a microscope type slide.
 10. The mount assembly asset forth in claim 9 which includes stop means to position a microscopeslide between the polarizing panes of said mount assembly.